lwn.git/net/nfc/llcp_sock.c, branch docs-fixes

net: Convert proto_ops connect() callbacks to use sockaddr_unsized

2025-11-05T03:10:32+00:00

Update all struct proto_ops connect() callback function prototypes from "struct sockaddr *" to "struct sockaddr_unsized *" to avoid lying to the compiler about object sizes. Calls into struct proto handlers gain casts that will be removed in the struct proto conversion patch. No binary changes expected. Signed-off-by: Kees Cook Link: https://patch.msgid.link/20251104002617.2752303-3-kees@kernel.org Signed-off-by: Jakub Kicinski

net: Convert proto_ops bind() callbacks to use sockaddr_unsized

2025-11-05T03:10:32+00:00

Update all struct proto_ops bind() callback function prototypes from "struct sockaddr *" to "struct sockaddr_unsized *" to avoid lying to the compiler about object sizes. Calls into struct proto handlers gain casts that will be removed in the struct proto conversion patch. No binary changes expected. Signed-off-by: Kees Cook Link: https://patch.msgid.link/20251104002617.2752303-2-kees@kernel.org Signed-off-by: Jakub Kicinski

net: change proto and proto_ops accept type

2024-05-14T00:19:09+00:00

Rather than pass in flags, error pointer, and whether this is a kernel invocation or not, add a struct proto_accept_arg struct as the argument. This then holds all of these arguments, and prepares accept for being able to pass back more information. No functional changes in this patch. Acked-by: Jakub Kicinski Signed-off-by: Jens Axboe

nfc: llcp: fix nfc_llcp_setsockopt() unsafe copies

2024-04-10T00:01:01+00:00

syzbot reported unsafe calls to copy_from_sockptr() [1] Use copy_safe_from_sockptr() instead. [1] BUG: KASAN: slab-out-of-bounds in copy_from_sockptr_offset include/linux/sockptr.h:49 [inline] BUG: KASAN: slab-out-of-bounds in copy_from_sockptr include/linux/sockptr.h:55 [inline] BUG: KASAN: slab-out-of-bounds in nfc_llcp_setsockopt+0x6c2/0x850 net/nfc/llcp_sock.c:255 Read of size 4 at addr ffff88801caa1ec3 by task syz-executor459/5078 CPU: 0 PID: 5078 Comm: syz-executor459 Not tainted 6.8.0-syzkaller-08951-gfe46a7dd189e #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:114 print_address_description mm/kasan/report.c:377 [inline] print_report+0x169/0x550 mm/kasan/report.c:488 kasan_report+0x143/0x180 mm/kasan/report.c:601 copy_from_sockptr_offset include/linux/sockptr.h:49 [inline] copy_from_sockptr include/linux/sockptr.h:55 [inline] nfc_llcp_setsockopt+0x6c2/0x850 net/nfc/llcp_sock.c:255 do_sock_setsockopt+0x3b1/0x720 net/socket.c:2311 __sys_setsockopt+0x1ae/0x250 net/socket.c:2334 __do_sys_setsockopt net/socket.c:2343 [inline] __se_sys_setsockopt net/socket.c:2340 [inline] __x64_sys_setsockopt+0xb5/0xd0 net/socket.c:2340 do_syscall_64+0xfd/0x240 entry_SYSCALL_64_after_hwframe+0x6d/0x75 RIP: 0033:0x7f7fac07fd89 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 91 18 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fff660eb788 EFLAGS: 00000246 ORIG_RAX: 0000000000000036 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007f7fac07fd89 RDX: 0000000000000000 RSI: 0000000000000118 RDI: 0000000000000004 RBP: 0000000000000000 R08: 0000000000000002 R09: 0000000000000000 R10: 0000000020000a80 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 Signed-off-by: Eric Dumazet Reported-by: syzbot Reviewed-by: Krzysztof Kozlowski Link: https://lore.kernel.org/r/20240408082845.3957374-4-edumazet@google.com Signed-off-by: Jakub Kicinski

nfc: Do not send datagram if socket state isn't LLCP_BOUND

2023-12-25T07:29:04+00:00

As we know we cannot send the datagram (state can be set to LLCP_CLOSED by nfc_llcp_socket_release()), there is no need to proceed further. Thus, bail out early from llcp_sock_sendmsg(). Signed-off-by: Siddh Raman Pant Reviewed-by: Krzysztof Kozlowski Reviewed-by: Suman Ghosh Signed-off-by: David S. Miller

net: nfc: Fix use-after-free caused by nfc_llcp_find_local

2023-06-26T09:57:23+00:00

This commit fixes several use-after-free that caused by function nfc_llcp_find_local(). For example, one UAF can happen when below buggy time window occurs. // nfc_genl_llc_get_params | // nfc_unregister_device | dev = nfc_get_device(idx); | device_lock(...) if (!dev) | dev->shutting_down = true; return -ENODEV; | device_unlock(...); | device_lock(...); | // nfc_llcp_unregister_device | nfc_llcp_find_local() nfc_llcp_find_local(...); | | local_cleanup() if (!local) { | rc = -ENODEV; | // nfc_llcp_local_put goto exit; | kref_put(.., local_release) } | | // local_release | list_del(&local->list) // nfc_genl_send_params | kfree() local->dev->idx !!!UAF!!! | | and the crash trace for the one of the discussed UAF like: BUG: KASAN: slab-use-after-free in nfc_genl_llc_get_params+0x72f/0x780 net/nfc/netlink.c:1045 Read of size 8 at addr ffff888105b0e410 by task 20114 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x72/0xa0 lib/dump_stack.c:106 print_address_description mm/kasan/report.c:319 [inline] print_report+0xcc/0x620 mm/kasan/report.c:430 kasan_report+0xb2/0xe0 mm/kasan/report.c:536 nfc_genl_send_params net/nfc/netlink.c:999 [inline] nfc_genl_llc_get_params+0x72f/0x780 net/nfc/netlink.c:1045 genl_family_rcv_msg_doit.isra.0+0x1ee/0x2e0 net/netlink/genetlink.c:968 genl_family_rcv_msg net/netlink/genetlink.c:1048 [inline] genl_rcv_msg+0x503/0x7d0 net/netlink/genetlink.c:1065 netlink_rcv_skb+0x161/0x430 net/netlink/af_netlink.c:2548 genl_rcv+0x28/0x40 net/netlink/genetlink.c:1076 netlink_unicast_kernel net/netlink/af_netlink.c:1339 [inline] netlink_unicast+0x644/0x900 net/netlink/af_netlink.c:1365 netlink_sendmsg+0x934/0xe70 net/netlink/af_netlink.c:1913 sock_sendmsg_nosec net/socket.c:724 [inline] sock_sendmsg+0x1b6/0x200 net/socket.c:747 ____sys_sendmsg+0x6e9/0x890 net/socket.c:2501 ___sys_sendmsg+0x110/0x1b0 net/socket.c:2555 __sys_sendmsg+0xf7/0x1d0 net/socket.c:2584 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3f/0x90 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x72/0xdc RIP: 0033:0x7f34640a2389 RSP: 002b:00007f3463415168 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007f34641c1f80 RCX: 00007f34640a2389 RDX: 0000000000000000 RSI: 0000000020000240 RDI: 0000000000000006 RBP: 00007f34640ed493 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffe38449ecf R14: 00007f3463415300 R15: 0000000000022000 Allocated by task 20116: kasan_save_stack+0x22/0x50 mm/kasan/common.c:45 kasan_set_track+0x25/0x30 mm/kasan/common.c:52 ____kasan_kmalloc mm/kasan/common.c:374 [inline] __kasan_kmalloc+0x7f/0x90 mm/kasan/common.c:383 kmalloc include/linux/slab.h:580 [inline] kzalloc include/linux/slab.h:720 [inline] nfc_llcp_register_device+0x49/0xa40 net/nfc/llcp_core.c:1567 nfc_register_device+0x61/0x260 net/nfc/core.c:1124 nci_register_device+0x776/0xb20 net/nfc/nci/core.c:1257 virtual_ncidev_open+0x147/0x230 drivers/nfc/virtual_ncidev.c:148 misc_open+0x379/0x4a0 drivers/char/misc.c:165 chrdev_open+0x26c/0x780 fs/char_dev.c:414 do_dentry_open+0x6c4/0x12a0 fs/open.c:920 do_open fs/namei.c:3560 [inline] path_openat+0x24fe/0x37e0 fs/namei.c:3715 do_filp_open+0x1ba/0x410 fs/namei.c:3742 do_sys_openat2+0x171/0x4c0 fs/open.c:1356 do_sys_open fs/open.c:1372 [inline] __do_sys_openat fs/open.c:1388 [inline] __se_sys_openat fs/open.c:1383 [inline] __x64_sys_openat+0x143/0x200 fs/open.c:1383 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3f/0x90 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x72/0xdc Freed by task 20115: kasan_save_stack+0x22/0x50 mm/kasan/common.c:45 kasan_set_track+0x25/0x30 mm/kasan/common.c:52 kasan_save_free_info+0x2e/0x50 mm/kasan/generic.c:521 ____kasan_slab_free mm/kasan/common.c:236 [inline] ____kasan_slab_free mm/kasan/common.c:200 [inline] __kasan_slab_free+0x10a/0x190 mm/kasan/common.c:244 kasan_slab_free include/linux/kasan.h:162 [inline] slab_free_hook mm/slub.c:1781 [inline] slab_free_freelist_hook mm/slub.c:1807 [inline] slab_free mm/slub.c:3787 [inline] __kmem_cache_free+0x7a/0x190 mm/slub.c:3800 local_release net/nfc/llcp_core.c:174 [inline] kref_put include/linux/kref.h:65 [inline] nfc_llcp_local_put net/nfc/llcp_core.c:182 [inline] nfc_llcp_local_put net/nfc/llcp_core.c:177 [inline] nfc_llcp_unregister_device+0x206/0x290 net/nfc/llcp_core.c:1620 nfc_unregister_device+0x160/0x1d0 net/nfc/core.c:1179 virtual_ncidev_close+0x52/0xa0 drivers/nfc/virtual_ncidev.c:163 __fput+0x252/0xa20 fs/file_table.c:321 task_work_run+0x174/0x270 kernel/task_work.c:179 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline] exit_to_user_mode_loop kernel/entry/common.c:171 [inline] exit_to_user_mode_prepare+0x108/0x110 kernel/entry/common.c:204 __syscall_exit_to_user_mode_work kernel/entry/common.c:286 [inline] syscall_exit_to_user_mode+0x21/0x50 kernel/entry/common.c:297 do_syscall_64+0x4c/0x90 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x72/0xdc Last potentially related work creation: kasan_save_stack+0x22/0x50 mm/kasan/common.c:45 __kasan_record_aux_stack+0x95/0xb0 mm/kasan/generic.c:491 kvfree_call_rcu+0x29/0xa80 kernel/rcu/tree.c:3328 drop_sysctl_table+0x3be/0x4e0 fs/proc/proc_sysctl.c:1735 unregister_sysctl_table.part.0+0x9c/0x190 fs/proc/proc_sysctl.c:1773 unregister_sysctl_table+0x24/0x30 fs/proc/proc_sysctl.c:1753 neigh_sysctl_unregister+0x5f/0x80 net/core/neighbour.c:3895 addrconf_notify+0x140/0x17b0 net/ipv6/addrconf.c:3684 notifier_call_chain+0xbe/0x210 kernel/notifier.c:87 call_netdevice_notifiers_info+0xb5/0x150 net/core/dev.c:1937 call_netdevice_notifiers_extack net/core/dev.c:1975 [inline] call_netdevice_notifiers net/core/dev.c:1989 [inline] dev_change_name+0x3c3/0x870 net/core/dev.c:1211 dev_ifsioc+0x800/0xf70 net/core/dev_ioctl.c:376 dev_ioctl+0x3d9/0xf80 net/core/dev_ioctl.c:542 sock_do_ioctl+0x160/0x260 net/socket.c:1213 sock_ioctl+0x3f9/0x670 net/socket.c:1316 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:870 [inline] __se_sys_ioctl fs/ioctl.c:856 [inline] __x64_sys_ioctl+0x19e/0x210 fs/ioctl.c:856 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3f/0x90 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x72/0xdc The buggy address belongs to the object at ffff888105b0e400 which belongs to the cache kmalloc-1k of size 1024 The buggy address is located 16 bytes inside of freed 1024-byte region [ffff888105b0e400, ffff888105b0e800) The buggy address belongs to the physical page: head:ffffea000416c200 order:3 entire_mapcount:0 nr_pages_mapped:0 pincount:0 flags: 0x200000000010200(slab|head|node=0|zone=2) raw: 0200000000010200 ffff8881000430c0 ffffea00044c7010 ffffea0004510e10 raw: 0000000000000000 00000000000a000a 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff888105b0e300: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff888105b0e380: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff888105b0e400: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888105b0e480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888105b0e500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb In summary, this patch solves those use-after-free by 1. Re-implement the nfc_llcp_find_local(). The current version does not grab the reference when getting the local from the linked list. For example, the llcp_sock_bind() gets the reference like below: // llcp_sock_bind() local = nfc_llcp_find_local(dev); // A ..... \ | raceable ..... / llcp_sock->local = nfc_llcp_local_get(local); // B There is an apparent race window that one can drop the reference and free the local object fetched in (A) before (B) gets the reference. 2. Some callers of the nfc_llcp_find_local() do not grab the reference at all. For example, the nfc_genl_llc_{{get/set}_params/sdreq} functions. We add the nfc_llcp_local_put() for them. Moreover, we add the necessary error handling function to put the reference. 3. Add the nfc_llcp_remove_local() helper. The local object is removed from the linked list in local_release() when all reference is gone. This patch removes it when nfc_llcp_unregister_device() is called. Therefore, every caller of nfc_llcp_find_local() will get a reference even when the nfc_llcp_unregister_device() is called. This promises no use-after-free for the local object is ever possible. Fixes: 52feb444a903 ("NFC: Extend netlink interface for LTO, RW, and MIUX parameters support") Fixes: c7aa12252f51 ("NFC: Take a reference on the LLCP local pointer when creating a socket") Signed-off-by: Lin Ma Reviewed-by: Simon Horman Signed-off-by: David S. Miller

net: remove noblock parameter from skb_recv_datagram()

2022-04-06T12:45:26+00:00

skb_recv_datagram() has two parameters 'flags' and 'noblock' that are merged inside skb_recv_datagram() by 'flags | (noblock ? MSG_DONTWAIT : 0)' As 'flags' may contain MSG_DONTWAIT as value most callers split the 'flags' into 'flags' and 'noblock' with finally obsolete bit operations like this: skb_recv_datagram(sk, flags & ~MSG_DONTWAIT, flags & MSG_DONTWAIT, &rc); And this is not even done consistently with the 'flags' parameter. This patch removes the obsolete and costly splitting into two parameters and only performs bit operations when really needed on the caller side. One missing conversion thankfully reported by kernel test robot. I missed to enable kunit tests to build the mctp code. Reported-by: kernel test robot Signed-off-by: Oliver Hartkopp Signed-off-by: David S. Miller

nfc: llcp: Revert "NFC: Keep socket alive until the DISC PDU is actually sent"

2022-03-03T10:43:37+00:00

This reverts commit 17f7ae16aef1f58bc4af4c7a16b8778a91a30255. The commit brought a new socket state LLCP_DISCONNECTING, which was never set, only read, so socket could never set to such state. Remove the dead code. Signed-off-by: Krzysztof Kozlowski Signed-off-by: David S. Miller

nfc: llcp: protect nfc_llcp_sock_unlink() calls

2022-03-03T10:43:37+00:00

nfc_llcp_sock_link() is called in all paths (bind/connect) as a last action, still protected with lock_sock(). When cleaning up in llcp_sock_release(), call nfc_llcp_sock_unlink() in a mirrored way: earlier and still under the lock_sock(). Signed-off-by: Krzysztof Kozlowski Signed-off-by: David S. Miller

nfc: llcp: use centralized exiting of bind on errors

2022-03-03T10:43:37+00:00

Coding style encourages centralized exiting of functions, so rewrite llcp_sock_bind() error paths to use such pattern. This reduces the duplicated cleanup code, make success path visually shorter and also cleans up the errors in proper order (in reversed way from initialization). No functional impact expected. Signed-off-by: Krzysztof Kozlowski Signed-off-by: David S. Miller